Amazon (AMZN)’s plans to expand its grocery offering AmazonFresh into up to 20 more new markets this year “could be a very quick disruption” for old-fashioned grocery stores, Deutsche Bank (DB)’s Karen Short said Friday.

For five years, Amazon’s AFresh same-day delivery service program was only available in Seattle, before the e-commerce giant launched it last year in LA and, six months later, San Francisco.

“The issue is that traditional grocery stores are really not paying attention to this as a potential threat,” Short said on CNBC’s “Fast Money.”

“We think the threat is much more imminent than grocers realize. And because of the razor-thin margin nature of the business, a 1 percent volume loss is a 10 percent EBITDA dollar loss—and getting a 1 percent share is not that high a bar for Amazon.

“Amazon can literally flip a switch and nobody knows where they have the infrastructure,” said Short. “They could be retrofitting existing facilities right now in the markets at their existing facilities and again, flip a switch, and suddenly they’re operating.”

Shares in the $149 billion company fell 0.34 percent on Friday to close at $324.57.